How the tire pressure monitoring system works


WHAT IS TPMS & HOW DOES IT WORK?

The purpose of the tire pressure monitoring system (TPMS) in your vehicle is to warn you that at least one or more tires are significantly under-inflated, possibly creating unsafe driving conditions. The TPMS low tire pressure indicator is a yellow symbol that illuminates on the dashboard instrument panel in the shape of a tire cross-section (that resembles a horseshoe) with an exclamation point.

That indicator light in your vehicle has a history. It’s a history rooted in years of uncertainty about proper tire pressure and many serious car accidents that might have been avoided had drivers known their air pressure was low. Even now, it’s estimated that a substantial number of vehicles hit the road each day with underinflated tires. However, proper tire maintenance with the aid of a TPMS can and does help prevent many serious accidents.

Before this indicator light became commonplace, knowing whether your air pressure had reached unsafe levels meant getting out, crouching down, and using a tire gauge. With few exceptions, this was the only pressure-checking tool ordinary consumers had at their disposal.

Then, in response to a surge in accidents due to underinflated tires, the US government passed the Transportation Recall Enhancement, Accountability, and Documentation (TREAD) Act. One of the outcomes of this legislation is that most vehicles sold in the United States since 2007 include a tire pressure monitoring system of some kind.

Not every TPMS works the same way. The illumination of the low tire pressure indicator represents the final step in the process of either an indirect TPMS or a direct TPMS.

INDIRECT TPMS: WHAT IS INDIRECT TPMS & HOW DOES IT WORK?

An indirect TPMS typically relies on wheel speed sensors that the anti-lock brake system uses. These sensors measure the rate of revolution each wheel is making and can be used by on-board computer systems to compare with each other and to other vehicle operation data such as speed.

Based on the rate of revolution of each wheel, the computer can interpret the relative size of the tires on your vehicle. When a wheel starts spinning faster than expected, the computer calculates that the tire is underinflated and alert the driver accordingly.

So, an indirect tire pressure monitoring system doesn’t actually measure tire pressure. It’s not electronically processing the same kind of measurement you might see with a tire gauge. Instead, an indirect tire pressure monitor simply measures how fast your tires are rotating and sends signals to the computer that will actuate the indicator light when something in the rotation seems amiss.

ADVANTAGES OF INDIRECT TPMS

-- Relatively inexpensive compared to a direct TPMS

-- Requires less programming/maintenance over the years than a direct TPMS

-- Less overall installation maintenance than its direct counterpart

DISADVANTAGES OF INDIRECT TPMS

-- May become inaccurate if you purchase a bigger or smaller tire

-- May be unreliable when tires are unevenly worn

-- Must be reset after properly inflating every tire

-- Must be reset after routine tire rotation

DIRECT TPMS: WHAT IS DIRECT TPMS & HOW DOES IT WORK?

Direct TPMS uses pressure monitoring sensors within each tire that monitor specific pressure levels – not just wheel revolution data from the anti-lock brake system.

Sensors in a direct TPMS may even provide tire temperature readings. The direct tire pressure monitoring system sends all of this data to a centralized control module where it’s analyzed, interpreted, and, if tire pressure is lower than it should be, transmitted directly to your dashboard where the indicator light illuminates. A direct tire pressure monitor usually sends all of this data wirelessly. Each sensor has a unique serial number. This is how the system not only distinguishes between itself and systems on other vehicles, but also among pressure readings for each individual tire.

Many manufacturers use proprietary technology for these highly specialized systems, so replacing a TPMS in a way that’s consistent and compatible with your vehicle will require an experienced, knowledgeable technician.

ADVANTAGES OF DIRECT TPMS

-- Deliver actual tire pressure readings from inside the tire

-- Not prone to inaccuracies because of tire rotations or tire replacements

-- Simple resynchronization after tire rotation or tire replacements

-- Batteries inside the sensors usually last for about a decade.

-- May be included in a vehicle’s spare tire

DISADVANTAGES OF DIRECT TPMS

-- More expensive overall than an indirect TPMS

-- Though simple, resynchronization may require costly tools.

-- Battery rarely serviceable; if the battery is drained, the whole sensor must be changed.

-- Proprietary systems make installation, service, and replacement confusing for consumers and auto shops.

-- Sensors are susceptible to damage during mounting/demounting

TIRE PRESSURE AND SAFETY

Although the methods may be different, both systems serve the same purpose and activate the same indicator light. Even though a TPMS can deliver accurate alerts when properly maintained, it’s not a replacement for manual air pressure checks, consider it just another item in your car maintenance toolbox.

CONTINUE YOUR JOURNEY

There’s never a good time for a flat. That’s why Bridgestone DriveGuard tires are masterfully engineered to keep you moving for up to 50 miles at speeds up to 50 MPH without disruption.

CONTINUE YOUR JOURNEY

There’s never a good time for a flat. That’s why Bridgestone DriveGuard tires are masterfully engineered to keep you moving for up to 50 miles at speeds up to 50 MPH without disruption.

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Tire Pressure Sensor: TPMS | Tires Plus

See why a TMPS is an important function of your vehicle and learn how to read it.

What is TPMS?

The Tire Pressure Monitoring System (TMPS) is an electronic system in your vehicle that monitors your tire air pressure and alerts you when it falls dangerously low.

 

 

Why do vehicles have TPMS?

To help drivers recognize the importance of tire pressure safety and maintenance, Congress passed the TREAD act, which requires most vehicles made after 2006 to be TPMS–equipped.

How does the Tire Pressure Monitoring System work?

There are two different types of systems being used today: Direct TPMS and Indirect TPMS.

Direct TPMS uses a sensor mounted in the wheel to measure air pressure in each tire. When air pressure drops 25% below the manufacturer’s recommended level, the sensor transmits that information to your car’s computer system and triggers your dashboard indicator light.

Indirect TPMS works with your car’s Antilock Braking System’s (ABS) wheel speed sensors. If a tire’s pressure is low, it will roll at a different wheel speed than the other tires. This information is detected by your car’s computer system, which triggers the dashboard indicator light.

What are the benefits of TPMS?

TPMS notifies you when your vehicle’s tire pressure is low or is going flat. By helping you maintain proper tire pressure, TPMS can increase your safety on the road by improving your vehicle’s handling, decreasing tire wear, reducing braking distance and bettering fuel economy.

Is my vehicle equipped with a Tire Pressure Monitoring System?

Your vehicle has TPMS if the "low tire pressure" warning light appears on your dash when the key is turned to the "on" position.

What should I do if my warning indicator comes on?

Check the air pressure in your tires and inflate any tire that is low (according to the manufacturer’s recommendation). When the tire is at the appropriate pressure, the indicator light should go off.

If necessary, replace the tire with your spare tire and visit your local Tires Plus store for needed repairs or replacement. They’ll check your vehicle’s tire pressure and perform a systems test on all of your tire sensors to diagnose the problem. Once our technicians address your vehicle’s tire needs, they’ll then suggest the proper maintenance to get you back on the road safely.

Why does tire maintenance with Direct TPMS cost more?

Direct TPMS equipped tires cost slightly more to maintain than non–equipped tires because proper care requires extra parts and labor. The valve service kit, which includes the valve core, cap, nut and o–ring (seal), must always be replaced when a tire is dismounted for service or replacement. A special TPMS tool and additional time are also needed to check and reset the sensor system.

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How does the tire pressure monitoring system work?

In America and Europe, a tire pressure monitoring system is an indispensable element of a car. Most likely, in the near future the same rules will be adopted in Russia.

But even if this system does not become mandatory, nothing prevents it from being installed in a car if the standard TPMS is not provided by the manufacturer: it is much better to find out in time that the wheel is flat than to wait for sad consequences.


TPMS (tire pressure monitoring system) monitors changes in tire pressure: even a small decrease in pressure in one wheel increases fuel consumption, worsens car handling and increases tread wear.

Now the pressure control system is divided into systems of direct (direct) and indirect (indirect) directions - we will tell you in more detail what it is.

How the direct system works

In direct measurement systems, sensors are placed on the valves of all wheels. They can be installed inside or outside. The sensor detects the level of pressure in the wheel and transmits information via radio to the control unit. Here, the accuracy of the readings plays a big role - you can even track a decrease in pressure by only 0.1 bar.


The "direct" system is more expensive than the "indirect" one, but it transmits information more accurately and faster. She, of course, has her own nuances: if you have to swap tires for even wear, then information about this will need to be entered into the control unit.

How the “indirect” system works

The so-called "indirect" TPMS is essentially a software extension for ABS: in its work it uses standard wheel rotation sensors. The system monitors changes in wheel speed and can diagnose tire pressure loss based on this information.

In this case, we are not talking about exact values, but only signals a significant deviation from the usual pressure - a significant deviation in this case is 0.3 bar, and a dangerous one is 0.5 bar.

"Indirect" systems may erroneously transmit a signal for a decrease in tire pressure also when:

  1. Uneven load distribution

  2. Frequent change from lane to lane

  3. slippage

  4. Sharp descents and ascents

But this can be adjusted, for example, by setting an alert delay. You can also reboot the system so that it adjusts to different tire pressures at startup.

TPMS from AIRLINE

The AIRLINE range includes 2 models of the "direct" system.

Tire pressure monitoring system TPMS BLACK ATP-MS-01 includes 4 sensors and a receiving module with a color LCD display. The sensors are mounted on the nipple of the car wheel, measure the pressure and air temperature in the tire and transmit information about the pressure value via radio to the display. When the tire pressure changes, the system transmits information with sound signals and displays it on the display. The pressure and temperature thresholds are set in the display menu. The system can be installed independently - it does not require special skills.


The receiving module is powered by the car's cigarette lighter socket, there is also a USB output for convenient parallel charging of the smartphone. The kit includes a receiver with a display, 4 external pressure sensors, 4 locknuts, a kit for mounting sensors, a warranty card and instructions. The operating temperature of the sensors is from -40°С to +125°С.

Tire pressure monitoring system TPMS wireless INSIDER SOLYAR ATP-MS-02 includes 4 sensors and a receiving module with a color LCD display. When the tire pressure changes, the system transmits information with sound signals and displays it on the display. The sensors are marked position, but the wheels can be swapped, everything is reconfigured. The operating temperature of the sensors is from -40°С to +125°С.


The kit includes a double-sided adhesive tape for fixing the receiving module on the dashboard of the car, it can also be mounted on a Velcro mat.

The receiver module is powered by a built-in lithium-polymer battery, which is charged by a built-in solar panel or a microUSB socket. The kit includes a receiver with a display, internal sensors, a USB-microUSB cable, double-sided tape, a warranty card and instructions. Tire fitting is required for installation, so we recommend contacting a service center for proper installation.

Tire pressure monitoring system - purpose, device, principle of operation

Home " Electrical equipment » Tire pressure monitoring system

The tire pressure monitoring system ( TPMS , Tires Pressure Monitoring System) is designed to warn of a dangerous change in tire pressure. This system is offered as an option when buying a car. The system can also be purchased and installed separately. The TPMS system has been installed on cars since 2000. Tire pressure monitoring systems are now mandatory in a number of European and Asian countries, as well as in the United States.

There are two types of tire pressure monitoring systems: indirect and direct pressure measurement. The simplest in terms of design is indirect pressure measurement system , which is a software extension of the ABS control unit. The principle of operation of this system is based on the fact that a flat tire has a smaller radius and, accordingly, travels a shorter distance in one revolution than a serviceable wheel.

The ABS wheel speed sensors measure the distance traveled by each tire in one revolution. The sensor signals are compared in the ABS unit with control parameters. If there is a discrepancy between the values, the indicator (control lamp) on the instrument panel lights up and an audible signal sounds.

The system provides adaptation to changes in tire pressure in the event of tire replacement or service work on the running gear - the so-called. system calibration . When driving in a new quality, the system evaluates and remembers the tire parameters. The calibration process gradually turns into the control of new tire pressure parameters.

The advantages of the indirect tire pressure measurement system are the absence of additional structural elements and the associated low cost. At the same time, the system has significant limitations in operation, including that it does not determine the pressure before starting to move, has low accuracy and a high threshold (30%) of the determined pressure deviation.

The direct pressure measurement system measures the pressure in each wheel using a suitable sensor. The system includes tire pressure sensors, a receiving antenna(s), a control unit and a display.

The tire pressure sensor is a complex device that combines a pressure sensor, a temperature sensor, measurement and control electronics, a battery and a transmitting antenna.

The sensor is installed on each wheel instead of the standard valve. Information from the sensor is transmitted by pulses with a frequency of, as a rule, one minute. The battery keeps the sensor working for 7-10 years. After the battery is discharged, the old sensor is replaced with a new one.

The receiving antenna receives signals from pressure sensors and transmits them to the control unit. The car's central locking antenna can be used as a receiving antenna. On some vehicles, an advanced version of the pressure monitoring system is installed, in which an individual antenna is used for each sensor. This allows you to control the pressure in a particular wheel and display its value on the information display. The antenna is installed in the wheel arch of the car body.

The control unit receives information from the sensors and compares the received data with the pressure control parameters. In the event of a pressure drop, the indicator (control lamp) on the instrument panel lights up, an audible signal sounds. These signals indicate that in some tire the pressure has dropped below the permissible level. In this case, the driver must stop the vehicle, check the pressure in each tire and determine the flat tire.

In the advanced version of the tire pressure monitoring system, in addition to the signals, textual and graphical information is displayed on the display. If there is an on-board computer, the computer display is used to display tire pressure information. The information provided allows you to identify the tire in which the pressure has decreased, as well as to estimate the actual pressure in it.

The direct measurement tire pressure monitoring system allows you to evaluate small, large and sudden changes in pressure. The system provides for adaptation to changing parameters in the event of a tire or pressure sensor replacement. In most modern systems, adaptation is performed automatically when the vehicle is moving at a certain speed for a certain time. A number of designs of TPMS systems after replacing tires (sensors) involve reprogramming using a special scanner.


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